Photographic silver halide emulsions sensitized with benzimidazole cyanine dyes

ABSTRACT

WHEREIN EACH OF GROUPS V1, V2, W1, and W2 is a hydrogen or halogen atom, each of groups R1 and R2 is a lower alkyl group, A is a group selected from polymethylene and alkylpolymethylene group, and n is an integer from 1 to 4.   A photographic silver halide emulsion having higher sensitivity and markedly reduced color staining incorporating a novel sensitizing dye represented by the general formula:

United States- Patent [1 1- Kimura et al.

[ 1 Feb. 19, 1974 22 Filed: Sept. 1,1972

21 Appl. No.: 285,694

Related US. Application Data [63] Continuation of Ser. No. 664,287, Aug. 30, 1967, abandoned.

[30] Foreign Application Priority Data Aug. 30, 1966 Japan.. 41-57141 [52] US. Cl 96/137, 260/240.6, 260/240.65 [51] Int. Cl G031: 1/18 [58] Field of Search 96/137 [56] References Cited UNITED STATES PATENTS 2,503,776 4/1950 Sprague...; ..Q6/137 2,945,763 7/1960 Jones 96/137 Primary Examiner-J. Travis Brown Attorney, Agent, or Firm-Sughrue, Rothwell, Mion,

Zinn & Macpeak 57 ABSTRACT A photographic silver halide emulsion having higher sensitivity and markedly reduced color staining incorporating a novel sensitizing dye represented by the general formula:

wherein each of groups V,, V,, W,, and W is a hydrogen or halogen atom, each of groups R, and R is a lower alkyl group, A is a group selected from polymethylene and alkylpolymethylene group, and n is an integer from 1 to 4.

5 Claims, No Drawings 1 PHOTOGRAPIIIC SILVER HALIDE EMULSIONS SENSITIZED WITH BENZIMIDAZOLE CYANINE DYES This is a continuation of application Ser. No. 664,287, filed Aug. 30, 1967, now abandoned and claiming priority from Aug. 30, 1966 based on Japanese Pat. application Ser. No. 357141/66.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to photographic silver halide emulsions containing a novel sensitizing'dye.

2. Description of the PriorArt It is known in the techniques of producing photo- 1 graphic silver halide emulsions that by adding a sensitiziiig dye to the silver halideemulsion the spectral of the image and has a bad influence on color reproduction in photographic color films.

Therefore, an object of this invention is to provide a photographic silver halide emulsion in which by employing an improved sensitizing dye, the formation of color stains is markedly reduced. Another object of this invention is to provide a photographic silver halide emulsion having a higher sensitivity than conventional silver halide emulsions.

SUMMARY OF .THE INVENTION The objects of this invention can be achieved by incorporating a novel sensitizing dye represented by the following general formula (A) in a photographic silver halide emulsion:

which is an asymmetrical benzimidazolocarbocyanine dye having a sulfoalkyl group as a substituent at the nitrogen atom of one nucleus and a carboxyalkyl group at the nitrogen atom of another nucleus, wherein V V W and W which may be the same or different, each represents a hydrogen atom, or a halogen atom, such as a chlorine atom, a bromine atom, an iodine atom or a fluorine atom; R, and R which may be the same or different, each represents a lower alkyl group, such as, a methyl group, an ethyl group, an n-propyl group, or an n-butyl group; A represents a polymethylene group, such as, an ethylene group, a trimethylene group or a tetramethylene group or an alkylpolymethylene group, such as, a methyltrimethylene group; and n is an integer of from 1 to 4.

dine, an anilinovinyl intermediate The sensitizing dye, asymmetrical benzimidazolocarbocyanine dye, may be prepared by a conventional. condensation process. Hereinafter, general processes of preparing an intermediate product for the sensitizing dye used in this invention and of preparing the sensitizing dye itself will be described.

A quaternary salt of benzimidazolium, which is an intermediate product of the sensitizing dye of this invention, may be obtained by reacting a benzimidazole with a-bromoacetic acid, ,B-bromopropionic acid, ,B-iodopropionic acid, 'y-bromobutyric acid, and'the like, but for preparing the pure-benzimidazolium quaternary salt with a good yield, a benzimidazole is caused to react with an acid amide compound or a nitrile compound of 5 the aforesaid carboxylic acid instead of reacting with the carboxylic acid to provide a quaternary salt, which is then hydrolyzed with a mineral acid such as hydrobromic acid to provide the quaternary salt of benzimidazolium having a carboxyalkyl group. By reacting the aforesaid quaternary salt with diphenylformamiproduct represented by the general formula (B) is prepared:

' R1 i V1 11; I I V I C-oH CH-N H-Q V; N

ermnoooa x ence of a suitable organic base, such as triethylamine or N-alkylpiperidine by adding the quaternary salt to the reaction solution, the benzimidazolocarbocyanine dye shown by formula (A) is obtained:

- v ri-SOF wherein W W R and A are as defined above in re- Jlll C OOH Br (2) The anilinovinyl intermediate shown by the above formula (1) may be prepared as follows:

A mixture of 4 g. of l--y-carboxypropyl-5,6-dichlorol 3-ethyl-2-methylbenzimidazolium bromide and 4 g. of diphenylformamidine washeated to 160 C on an oil bath and after removing under reduced pressure the aniline thus formed, the reaction was continued for 1 hour more. After the end of the reaction, the crystal 20 obtained was washed with acetone to provide 3.7 g. of the light-yellow crystal having a melting point of 220 The anilinovinyl intermediate product shown by formula (2) may be also prepared by a similar process as 25 used to prepare compound (1). The melting point thereof was 215 C.

Typical examples of sensitizing dyes used in this invention are as follows:

The sensitizing dye shown by formula (I) may be prepared as follows:

4.7 g. of the intermediate product (2), 2-(B- anilinovinyl)-1-carboxymethyl-5,6-dichloro-3- ethylbenzimidazolium bromide was heated under refluxing for 15 minutes in a mixture of 2 ml. of acetic anhydride and 20 ml. of nitrobenzene. The resulting solution was mixed with 3.8 g. of anhydro-5,6-dichloro-lethyl-2-methyl-3-(3-sulfobutyl)-benzimidazolium hydroxide and 2 ml. of triethylamine and the mixture was heated under refluxing for 10 minutes. After cooling, ether was added to the product to precipitate the dye. The precipitate was washed with water and recrystallized from a mixed solution of methanol and chloroform to provide 1.2 g. of the crystals of the sensitizing dye (I) having a melting point of 238 C (decomposed). The spectral absorption maximum of the dye in methanol was 518 m.;:..

Sulfur analysis: calculated: 4.84%, Found: 4.61%.

Sensitizing dye (II) was also obtained by the same procedure as above. The melting point of the dye was 270 C (decomposed), and the spectral absorption maximum of the dye in methanol was 513 m.p..

' Sulfur analysis: calculated: 4.98%, Found: 4.73%.

Sensitizing dye (111) was also obtained by the same procedure. The melting point thereof was 284 C. (decomposed), and the spectral absorption maximum of the dye in methanol was 518 m.p..

Sulfur analysis: calculated: 4.73%, Found: 4.65%.

Sensitizing dye (IV) was also obtained by the same procedure as in the case of preparing dye (l). The melting point thereof was 236 C. (decomposed), and the spectral absorption maximum of the dye in methanol was 518m.p..

Sulfur analysis: calculated: 4.84%, Found: 4.68%.

In the silver halide emulsion used in this invention may be used various silver salts, such as silver chloride, silver bromide, silver iodide, silver iodobromide, and the like.

In order to prepare the sensitized photographic silver halide emulsion of this invention, one or more of the sensitizing dyes may be incorporated into the photographic silver halide emulsion by a conventional method.

Since the concentration of the sensitizing dye in the emulsion may be in a range of from 1 to 150 mg. per one kg. of the emulsion, the concentration thereof may be varied in the wide range according to a desired effect.

The sensitizing dye used in this invention may be incorporated into a photographic silver halide emulsion which had been sensitized by physical repening and chemical repening.

Moreover, in the production of the photographic silver halide emulsion, there may be added to the emulsion by a conventional method additives such as a sensitizer, a stabilizer, a color toning agent, a hardening agent, a wetting agent, an anti-foggant, a plasticizer, a development accelerator, a coupler and a fluorescent whitening agent.

The photographic silver halide emulsion of this invention may be applied to a suitable support such as a glass plate, a cellulose derivative film, a synthetic resin 5 film or a baryta paper.

5 sion, it sensitizes spectrally the silver halide emulsion and, in particular, in the case of a gelatino silver halide emulsion it enlarges the spectral light-sensitive range of the emulsion. Furthermore, the sensitizing dye can also be used as a sensitizer for a photographic silver halide 5 TABLE 4 emulsion containing a hydrophilic colloid other than gelatin such as agar agar collodion, water'soluble Test sensitizing Amount (mg. Emulsion Density of cellulose derivative, polyvinyl alcohol, etc., or other No. Dye mole/ kg. Color Stain hydrophilic synthetic or natural resin. 1 emurlsm) When the photographic silver halide light-sensitive 1O 1 r 0.09 AgBr-CI 0.02 element having the silver halide emulsion layer con- 2 004 s 3 (u 0.08 AgBr-Cl 0.03 taming the novel sensitizing dye of this invention is sub- 4 (VW 0'04 Agape] 0'05 jected to photographic processings, such as developing, 5 AgBr-Cl fixing and water washing, coloring of the image-bearing 6 (vy AgBr'cl Q08 layer by the remaining dye is very low and further, W since the sensitizing dye has a low co-action to a coms iti i d (V) and (VI) have the following pound having an anionic group, such as a surface active Structures d were d f comparison; agent, color coupler and the like, the color sensitizing j property of the dye is not affected by the presence of 11 C2115 such an anionic compound. 1 1 1; EXAMPLE 1 C-CH -CH-CH=O JV A silver iodobromide emulsion (the mole ratio of AgI 01 to AgBr was 7:93) or a silver chlorobromide emulsion (1km? E (V) (the mole ratio of AgBr to Agl was 40:60) each con- I taining the sensitizing dye of this invention was applied to a film base and dried. The film thus prepared was ex- 1, posed to day light of 64 lux (5,400 K) through Fuji No. C1 3 Filter (made by Fuji Photo-Film Co.; passing light C CH=CH CH=C having wave lengths longer than 500 mJL.) and devel- 01 Ol oped. As the developer, one having the composition N N shown in Table l was used for the silver iodo-bromide 6 5 v1 emulsion layer and one having the composition shown in Table 2 was used for the silver chlorobromide emul- What is claimed sion layer. The results are shown in Table 3 and Table A photographic Silver halide emulsion containing I a sensitizing dy r name??? b rheeensta l rmla... v.;

TABLE 1 R1 R2 N-Methyl-p-aminophenol 20 g. 40 N l I W Hydroquinone 5.0 g. v I Sodium Sulfite 38 I 053; To Make 1000 mi? V \fi (011.)..00011 il-sor TABLE 2. a... --w -m,

wherein each of groups V V W and W which may N-methyl-p-Aminophenol Sulfate 20 g. be the smae or different, represents a member selected fig 2- from the group consisting of a hydrogen atom and a Sodium Carbonate (Anhydrous) 24 g: halogen atom, each of groups R and R which may be Potassium Bromide 1 the same or different, represents a lower alkyl group, water To Make A represents a member selected from the group con- TABLE 3 Test No. sensitizing dye Amount Emulsion Sensitizazion lglaximum Sensitivity l (l) 0.09 AgCl-Br 575-580 950 2 u 0.08 AgCl-Br 574-578 900 3 (II!) 0.04 AgCl-Br 575-580 v 950 4 (l) 0.09 AgBr l 577-580 980 5- (u 0.08 AgBr-l 576-578 950 6 (III) 0.04 AgBr-l 576-584 I 160 ()z m. g. mul/kg. of emulsion The sensitivity value was'determined when the silver iodobromide emulsion was exposed through Fuji No. 3

6. Filter, while defining the sensitivity of the silver iodobromide emulsion, containing no novel sensitizing dye of this invention, to be 100.

sisting of a. polymethylene group and an alkylpolymethylene group, and n is an integer from 1 to 4.

7 8 2. A photographic silver halide emulsion as claimed 4. A pohtographic silver halide emulsion as claimed in claim 1, wherein said sensitizing dye is in claim 1, wherein said sensitizing dye is C1115 C2115 (1 m 01m 1 I A; it N 01 ()l- \C:CH-,-CH=OHC I c=oncn=onc I 01 N/ \I:/ c1

' 01-1 COOII 1-1 so- 611200011 (cHmsm- 10 m .t e m a 5. A photographic silver halide emulsion as claimed 3. A photographic silver halide emulsion as claimed i lai 1, wherein said sensitizing dye is in claim 1, wherein said sensitizing dye is 

2. A photographic silver halide emulsion as claimed in claim 1, wherein said sensitizing dye is
 3. A photographic silver halide emulsion as claimed in claim 1, wherein said sensitizing dye is
 4. A pohtographic silver halide emulsion as claimed in claim 1, wherein said sensitizing dye is
 5. A photographic silver halide emulsion as claimed in claim 1, wherein said sensitizing dye is 